Bicycle crank change speed mechanism



April 16, 1940. 2,197,238

M. ECKENRODE BICYCLE CRANK CHANGE SPEED MECHANISM Filed Oct. 23, 19s? 2Sheets-Sheet 1 j INVENTOR. Mark Zeke/7 raae ATTORNEY.

April 16, 1940. M. ECKENRODE Q 2,197,238

' BICYCLE CRANK CHANGE SPEED MECHANISH' I Filed 001:. 23. 1937 w 2Sheets-Sheet 2 INVENTOR. Mark Eek 6nrode ATTORNEY.

Patented Apr. 16, 1940 Parent OFFjl-CE BICYCLE CRANK CHANGE SPEEMECHANISM I Mark Eckenrode, San Diego, Calif.

Application October 23, 1937, Serial No. 170,621

3 Claims.

My invention relates to a bicycle crank change speed mechanism so thatthe speed of the crank is changed relatively to the speed of the rearwheel of the bicycle, and the objects of my invention are:

First, to provide a bicycle crank change speed mechanism for changingthe speed of the bicycle relatively to the speed of the crank shaft sothat the bicycle may easily be propelled uphill;

Second, to provide such a change speed mechanism in which threedifierent speeds may be readily obtained;

Third, to provide a change speed mechanism of this class which operatesdirectly with the crank shaft of the bicycle;

Fourth, to provide such a change speed mechanism that is enclosed in acasing surrounding the crank shaft of the bicycle;

Fifth, to provide a change speed mechanism of this class which isapplicable to the conventional bicycle frame, the crank hanger onlybeing that it is easily shifted by the bicycle rider; and

Eighth, to provide a bicycle crank change speed mechanism of this classwhich is very simple and economical of construction, easy to operate,efiicient in its action, and which will not readily deteriorate or getout of order.

With these and other objects in view as will appear hereinafter, myinvention consists of such novel features of construction, combination,andarrangement of parts and portions as will be hereinafter described indetail and be particularly set forth in the appended claims, referencebeing had to the accompanying drawings and to the characters ofreference thereon which form a part of this application in which:

.Figure l is a sectional view of my bicycle crank change speed mechanismtaken from the line l of Fig. 2 showing some of the parts in elevationto facilitate the illustration and showing the operating lever in avarying position by dash line; Fig. 2 is a sectional view taken from theline 2-2 of Fig. 1 showing some of the parts in elevation to facilitatethe illustration and showing the portions of the frame at the crankhanger fragmentarily; Fig. 3 is a sectional view taken from the line 33of Fig. 1; Fig. 4 is a sectional view taken from the line 44 of Fig.

Fig. 5 is a sectional view taken from the line 5-5 of Fig, 1; and Fig. 6is a fragmentary sec-,

tional view of the gear portion of my mechanism showing the same inamodified form for only two speeds.

Similar characters of reference refer to similar parts and portionsthroughout the views of the preferredform:

The-main shaft I, crank members 2 and 3, sleeve and gear member 4,shiftable gear member 5, gear member 6, bearings I, 8, 9 and I0, casingmembers H and i2, sleeve l3,shift lever 14, spacer member If, crankhanger member l6 and sprocket ll constitute the principal parts andportions of my bicycle crank change speed mechanism.

The main shaft l is positioned in the crank hanger portion of thebicycle frame. Secured on the one end is a crank member 2 and on theopposite end a crank member 3. This crank shaft 4 is provided witha mainrelatively large portion Ia and at one end with a reduced portion I bupon which the crank 3 is secured. At the other end of the large portionla is provided a splined portion lc. Extending from this splined portionI0 is a smooth portion id to which the crank member 2 is secured.Shiftably mounted on the splined portion k: of the shaft l is theshiftable gear member 5, which is provided with a relatively large spurgear portion 5a at one end and with a relatively small gear portion 51)at its opposite end and intermediate said gear portions 5a and 5b is anannular groove 50 in which the extended portion Ma of the shift lever I4extend to provide means for shifting the gear member 5. This lever I4 isa bifurcated lever as shown best in Fig. 2 of the drawings and isprovided with a single lever portion Mb which is pivotally mountedbetween the lugs Ha and llb on the casing member H, shown best in Fig. 2of the drawings. This lever is also provided with an extended leverportion Me in the end of which is pivotally mounted rod Md which isadapted to extend upwardly in the reach of the rider for shifting thelever M for changing the speed of the crank. Mounted around the largerportion la of the shaft 0 and in which the shaft I is revolubly mountedis a sleeve and gear member 4. The sleeve portion to is provided on itsouter surface with bearing members 8 and 9 which are preferably ballbearing, and

interposed between the ball bearings 8 and 9' and surrounding the sleeve40, is a spacer memprovided with an enlarged portion 4b at one end whichprovides a shoulder 40, and against this shoulder is provided a spacermember 8a which forms a support for the one side of the bearing 8 shownbest in Fig. 1 of the drawings. Positioned on the outer end of themember 4b are external gear teeth 4d and internal clutch teeth 46 shownbest in Fig. 1 of the drawings. These internal clutch teeth le areadapted to mesh with the gear teeth 512 on the gear member 5 when theshift lever is positioned substantially half way between the positionshown by solid and dash lines in Fig. 1 of the drawings.

Supported on the outer surfaces of the bearings 8 and 9 is a casingmember II which is provided with an extended casing portion IIc whichextends downwardly some distance and in which is mounted a gear shaft 6aupon which the gear member 6 is revolubly mounted by means of bearings6b. This gear member 6 is "provided with intermediate sized gear teeth60, large gear teeth 6d, and small gear teeth be. The gear teeth 6e areadapted to mesh with the gear teeth 50: on the gear member 5 when theshift lever I4 is shifted to the dash line position shown in Fig. 1 ofthe drawings, in which case the gear teeth 50 are positioned inwardly sothat they do not engage the gear teeth (id or the clutch teeth ie, andare not in mesh. When the shift lever I4, how- 3 ever, is in theposition shown by solid lines, the

gear 52) meshes with the gear teeth 6d. Mounted on the one end of thecasing member II and conforming to the shape of said end is a casingmember I2, which supports the one end of the shaft to. This casing isprovided with a recessed portion IZa. which is adapted to receive thegear teeth portion 5a ofthe gear member 5 when in the position shown bysolid lines in Fig. 1 of the drawings. This casing I2 is also providedwith another smaller recess I222 in which is mounted the bearing 1 whichsupports the one end of the shaft I and engages the portion Id of saidshaft. The inner edge of the casing member I2 is provided with a grooveI20, which is provided to receive a portion of a packing member I201 toprevent the leakage of oil from. the casing member I2 around the shaftI. The casing members I I and I2 are secured together by means of boltsIZ e. Mounted around the end lb of the shaft I and the end of the sleeveportion 4a is another sleeve member I3, the one end of which restsagainst the bearing member 9 on the opposite side from the spacer memberI5. It is provided with an enlarged portion I30. forming a shoulder I32;against which rests a nut 4 which is screw threaded on the end of theportion 4a of the member Ii. Against this nut M and the end of theportion 4a rests a bearing II] which engages the portion of the shaftlb. The outer surface of this bearing Ill engages the inner side of theenlarged portion I30, of the casing member I3 and supports said casingmember relatively to the shaft portion lb. The outer end of thisenlarged portion iSa. of the casing member I3 is internally threaded andin which is screw threaded a nut Ito which is provided with a groove 83din its inner edge which is adapted to receive a packing member I3e forclosing the joint between the nut I30 and the shaft portion lb, thusproviding an oil tight joint at this .end of the shaft I. This casingmember I3 is provided with an upwardly extending flange portion Itagainst the one side of which the I sprocket IT is supported and is heldrigidly by means of a nut I'Ia which is screw threaded on the outer sideof the portion I311. of the casing I3 and against the outer side of thesprocket II, all as shown best in Fig. 1 of the drawings. It will behere noted that the sprocket II is splined on the casing I3 and thecasing I3 is splined on the sleeve portion Ga. The casing member II isinternally threaded at Me adapted to receive a nut III which restsagainst the bearing 9. It is also externally threaded and adapted toreceive a nut Hg. This nut! Ig rests against an L member Ifia. whichengages the one end of the hanger member I6. The other end of the hangermember I6 engages a shoulder Ilh and the member II. The one end of thehanger member I6 is notched to receive a key member I60 which enters anotch H5 in the casing II for preventing the casing member I I fromturning in the hanger member IS. The bearings 8 and 9 are set intothe'portion of the casing member II as shown best inFig. 1 of thedrawings. It will be noted that the gear member 5 is splined on thesplined portion Ic of the shaft I and is therefore shiftablelongitudinally on said shaft, but must turn with said shaft, and isshifted longitudinally thereon by means of the lever I4 for changing thespeed of the crank relatively to the speed of the sprocket IT.

The main shaft portion I is provided with a small bore Ie (Fig. 4) inwhich is mounted a spring If and a ball is supported in the end of saidrecess against said spring, designated Ig, and the gear member 5 isprovided with three spaced recesses 5d, which are adapted to be engagedby the balls lg when the member 5 is shifted along the shaft, thusproviding a definite stop and position of the shiftable gear member 5when it is shifted to the three various positions for the threedifferent speeds.

In the modified form of construction shown in Fig. 6 of the drawings thestructure is the same as that of the other views 1 to 5 inclusive exceptthat a slightly shorter shaft I8 is used and a shift gear andintermediate drive gear and direct drive gear are arranged for twospeeds only instead of three and are arranged as follows: The portion I8a of the shaft I 8 is splined and on this splined portion of the shafta shift gear I 9 is arranged which is provided with splined grooves sothat the gear I9 revolves with the shaft but may be shiftedlongitudinally thereon. It is provided with a groove Isa which isadapted to receive the bifurcated inturn lug portions of a shift lever20 which is substantially thesame as the shift lever M in the otherfigures of the drawings, but is slightly shorter because the casing isslightly smaller upon which it is mounted and the shift gear I9 is notshifted so far so that the movement is less. This shift gear It isprovided, with gear teeth portion I92) which is adapted to mesh withgear teeth portions 2 Ia of the sleeve and gear member 2I when the gearmember I9 is shifted in one direction. The intermediate gear 22 issupported substantially the same as the intermediate gear 6 in the otherfigures of the drawings. It, however, is provided with gear teethportion 22a which mesh with the gear portion IS?) on the shifting gearI9 when in the position shown in Fig. 6 of the drawings. When the gear I9 is shifted along the shaft I8, the teeth I9b engage the internal gearteeth Zla of the sleeve and gear member 2| and the gear member M is thenrevolved by the shift gear I9 and carries with it gear 22 by means ofthe teeth 221) on the gear 22 meshing with the external teeth 2|b on thesleeve and gear member 2|.

The operation of the preferred form is substantially as follows: Thedrive sprocket I1 is seing gear is shifted to the next notch controlledV by the ball lg shown best in Fig. 4 of the drawings, the mechanism isthen in intermediate speed and the gear teeth 5?) then mesh with theinternal clutch teeth 4e and revolve the member 4 directly. When theshifting. gear 5 is shifted the full distance from the solid lineposition, the gear teeth 5a then mesh with the gear teeth 6e and revolvethe gear 6 and carry the gear memher through the gear teeth Re by meansof the external gear teeth 4d.

The operation of the modified form is substantially the same. The shiftgear member is only, however, provided with one tooth portion whicheither engages the tooth portion 22a on the gear member 22 or theinternal teeth portion 21a of the gear member 2!, thus providing for twodifferent speeds. The member 2! is connected at its opposite endsubstantially the same as the member 4.

Though I'have shown anddescribed a particular construction, combination,and arrangement of parts and portions and a certain modificationthereof, I do not wish to be limited to this particular construction,combination and arrangement, nor to the modification but desire toinclude in the scope of my invention, the construction, combination, andarrangement sub stantially as set forth in the appended claims.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent is:

1. In a bicycle crankvchange speed mechanism of the class described, thecombination of, a crank shaft splined at one end, a splined shiftablegear shiftable longitudinally thereon provided; with two difierentdiameter teeth thereon only, a drive gear and sleeve mounted on saidshaft revoluble therewith provided with both internal and external teethportions at one end, and an intermediate gear provided with three-setsof teeth positioned to mesh with both of said gear members whereby, uponselective adjustment of the shiftable gear 3 driving ratios may beobtained.

v2. In a bicycle crank change speedmechanism of the class described, thecombination of, a crank shaft splined at one end, a splined shiftablegear shiftable longitudinally thereon provided with two differentdiameter teeth thereon only, a-drive gear and sleeve mounted on saidshaft revoluble therewith provided with both internal and external teethportions at one end, an intermediate gear provided with three setsofteeth, positioned to mesh with both of said gear members, and asprocket secured in cooperative relation With said sleeve and gearwhereby, upon selectiveadjustment of the shiftable gear 3 driving ratiosmay be obtained. I

3. In a bicycle crank change speed mechanism of the class described, thecombination of, a crank shaft splined at one end, a splinedshiftable'gear shiftable longitudinally thereon provided with twodifferent diameter teeth thereon only, a drive gear and sleeve mountedon said shaft revoluble therewith provided with both internal andv andgear, and a bell crank lever operatively connected with said shiftablegear arranged to shift said gear longitudinally on the splined end ofsaid shaft whereby, upon selective adjustment I of the shiftable gear 3driving ratios may be obtained.

